An apparatus and a method for authenticating policy based domains and tracing paths at the time of high-reliable data plane transmission according to the related art request paths from a sender to a destination to a path server and authenticate each domain participating in the paths. The authenticated contents are embedded into packet headers to be transmitted and are encrypted and transmitted. Received domains confirm whether headers are authenticated to go through the corresponding domains and whether headers go through all the paths that are to be go through until being reached to the corresponding domains and then, correct and transmit the headers. Since the method according to the related art embeds headers having a predetermined length corresponding to the number of domains that is to go through from the senders, when the number of domains to go through is increased, the lengths of the headers are variably long, such that time to be processed on the data plane may be increased and overhead occupied by all the packets may also be increased.